On a carton die the creasing directly shapes how the product looks on the shelf: with the wrong channel the fold line bursts, the lid does not seat or the box loses its shape. The input to the channel decision is not the grammage usually written alone on the order, but the real thickness, the grain direction and the surface finish. When those three arrive together the crease comes out right on the first sample.

Grammage and thickness are not the same thing

Grammage describes mass per area, thickness the cross-section of the sheet; two boards of the same grammage made at different bulk come out at different thicknesses. Because the crease channel works from thickness, board described by grammage alone leaves guesswork in the channel choice.

The measured thickness or the supplier’s product name is therefore added beside the grammage on the order; film, varnish or lamination is stated because the surface finish changes how the board folds. The safest check is a sample of the real material: the workshop measures the thickness itself and opens the channel to it.

  • Measured thickness or the supplier’s product name is written with the grammage.
  • Film, varnish or lamination is stated on the order.
  • A sample of the real material is the safest input to the channel choice.

Grain direction changes the fold line

Folds along and across the grain do not respond alike: a crease across the grain resists more and is more prone to cracking, a crease along the grain folds more easily. When one edge of the same box folds cleanly and the other cracks, the cause is usually not the channel but where that line sits relative to the grain.

On small lids and heavily printed areas the difference shows more; a wrong crease makes the lid hard to close and leaves a white crack line along the printed fold. The fold direction is stated on the drawing, critical lid dimensions are marked and the cracking risk in heavily printed areas is noted.

  • Critical lid dimensions and fold direction are marked on the drawing.
  • Folds across the grain are checked separately for cracking on the sample.
  • Cracking risk in heavily printed areas is noted on the order.

Channel width affects tolerance

A crease channel that is too narrow breaks the board fibres and shows as cracking in the print; one that is too wide lets the fold line wander and the box bulges or folds loosely. The channel is chosen wide enough to seat the fold exactly on the line without pinching the board; on thick board the channel widens, on thin board it narrows.

The counter channel is built in one of two ways: an adhesive creasing matrix or a form-specific pertinax counter. For a short job with few channels the matrix is a quick make-ready; on a multi-channel, repeating form a one-piece creasing counterplate improves setting consistency. Critical bends are marked and the proof expectation is shared at the start.

  • The channel is assessed from board thickness; narrow cracks, wide wanders.
  • Critical bend positions are marked on the drawing.
  • Proof expectation and counter type (matrix / pertinax) are discussed at the start.

How creasing is described in a quote request

Sending only the outer cut line is incomplete information for most cartons. Cut, crease and perforation lines come in separate colours or layers, fold positions are given with dimensions, and the lid and lock zones are marked in particular. One of two identical-looking lines turning out to be a crease is an irreversible error in production.

When material name, grammage and thickness, grain direction, surface finish and expected quantity are written together in the quote message, the workshop chooses channel and counter without guessing. The first sample is checked folded; lid fit and cracking on the line are the final test of the creasing decision.

  • Crease lines are separated from cut lines by colour or layer.
  • Fold positions carry dimensions; lid and lock zones are marked.
  • Material, thickness, grain direction and surface finish go together in the quote message.

Quote details we clarify together

When the file, material, quantity and deadline are clear, the quote conversation moves faster and with less back-and-forth.

  • Current revision file
  • Material and quantity details
  • Critical dimensions or production notes
  • Deadline expectation and delivery preference